i agree with Hot Rod Linkoln- you should check the starter. if your battery is bad, and your missing a ground strap here and there, its still not going to make your wires get hot; however an unfused ground (such as a short in the starter) will make the wires heat up even with a bad battery and a couple missing ground straps. if your still concerned about the block not being grounded grounded well- check the ohms between the neg terminal and the block. after having had some troubles with shorts on one of my cars i took to fusing the pos. cable right out of the gate; a 180 fuse wont protect from some of the smaller shorts, but it does give peace of mind that if the pos. cable shorts out (say it melts to a header or something) it wont ruin anything, just pop the fuse.

66' Chevy C-30 Rat